Revealing mistake: In the beginning of the film, Bruce Banner's hair is a dark brown and looks natural. When he is doing the anger control exercises, he is obviously wearing a black wig which is not natural looking at all. This happens a few times during the movie - it switches from his natural hair to the very dark wig. And at times, even his eyebrows look much darker and thicker.
Revealing mistake: In the scene where Bruce is in the helicopter hearing about the other "hulk", the camera is the only thing being moved around to simulate a shaky helicopter ride. The equipment nor any of the actors inside the copter are moving around or stabilizing themselves according to how bumpy the camera movements are making it out to be.